This invention relates to a storage system.
Storage systems have conventionally employed a scheme that configures a RAID (redundant array of inexpensive disks) group with a plurality of storage devices to provide a host computer with a logical volume created based on the RAID group.
As a technique related to RAID, PTL1 discloses a so-called distributed RAID that manages stripes including normal data and redundant data for restoring the normal data by distributing them to a plurality of storage devices providing their storage areas to a capacity pool.
Specifically, PTL1 discloses: A storage system is equipped with: multiple storage devices; and a control unit that provides predetermined storage areas of the multiple storage devices to a host computer as a virtual volume group that includes one or more virtual volumes. The control unit configures one or more data sets having a redundancy level of one or greater from the multiple storage devices, provides a storage area for a capacity pool which includes the multiple data sets to portions of the storage areas of the virtual volumes, limits the combinations of storage devices for configuring the data sets to be allocated to a virtual volume to a fixed number of combinations equal to or greater than two, evenly disperses the storage devices that appear in the fixed number of combinations in the storage area inside the capacity pool, and uses a fixed number of different combinations of storage devices to be allocated to the virtual volumes per virtual volume group (Abstract).
Meanwhile, Server SAN storage system is known as a type of distributed storage system, in which a plurality of servers (computers) are connected by a network to create a capacity pool. A Server SAN storage system uses local storage devices connected directly with server nodes as terminal storage; write data and its redundant data are distributed to the plurality of server nodes to protect the data.